1. Technical Field
The present invention relates to a washing apparatus that washes washing articles. The present invention particularly relates to a washing apparatus that washes washing articles in a washing tub which is filled with a cleaning liquid including water, a petroleum solvent or an organic solvent and the like.
2. Background Art
As a conventional washing apparatus, such a washing apparatus becomes popular not only as is provided with a washing tub, wherein a rotating axis is formed in a vertical direction, but also as is provided with a washing tub, wherein the rotating axis is formed in a horizontal direction or in a direction to be inclined from the horizontal direction (to be referred as “a horizontally inclined direction” hereafter). Then, the washing apparatus being provided with a washing tub, in which the rotating axis is formed vertically, generates a rotating flow (a swirling water current) in the cleaning liquid inside the washing tub, by rotating a pulsator that is installed to the bottom of the washing tub. By a force of the rotating flow of the cleaning liquid that is generated, washing articles such as clothes and the like are rubbed each other (a principle of rubbing wash), so that the washing articles are washed. On the other hand, a washing apparatus that is provided with a washing tub, wherein the rotating axis is formed in a horizontal direction or in a horizontally inclined direction, moves a washing article to the upper side of the washing tub with baffles being protruded on the inside wall surface of the washing tub, by rotating the washing tub, and subsequently has the washing article drop by its own weight. When the washing article drops, the washing article is washed by an impact force that is caused by an impact against the inside wall surface of the washing tub (a principle of beating wash).
A cleaning liquid that is used for washing by aforementioned washing apparatus is categorized into water or a water type of cleaning liquid such as a solvent in which a surface acting agent is mixed with water; and a non-water type of cleaning liquid such as a petroleum solvent or an organic type solvent and the like. When the water type of cleaning liquid is used, contamination of water solubility that is attached to a washing article is washed off. However, depending on a clothing fabric or fiber of the washing article, the washing article is susceptible to hardening or damage, which worsens the condition of the washing article after washing. On the other hand, when the non-water type of cleaning liquid is used, it is possible to avoid a danger of having the washing article damaged in such a case as when the water type of cleaning liquid is used, but the contamination of water solubility cannot be completely eliminated and washed off.
For the above mentioned inconvenient case, the present applicant proposes a washing method (See Patent Publication 1.) and a washing apparatus (See Patent Publication 2.). In Patent Publication 1 and Patent Publication 2, the cleaning liquid fills the casing which includes the washing tub having its center axis in the horizontal direction, and the washing tub is rotated. As the result, the washing article being contained inside a washing tub is made to float inside a cleaning liquid and is washed. In each of the washing method of Patent Publication 1 and the washing apparatus of Patent Publication 2, the washing tub is rotated, in which concaves and convexes are provided to the inside wall surface thereof continuously in a circumferential direction. Consequently, swirling water currents are generated for each concave and convex of the inside wall surface of the washing tub in the cleaning liquid on the side of the inside wall surface of the washing tub. By having the swirling water currents formed continuously along the inside wall surface of the washing tub, a large flow is generated along the rotation of the washing tub in the cleaning liquid inside the washing tub. Because the swirling water currents and a large flow that are generated in such a manner as mentioned above influence the washing article, the washing article is made to float and spreads inside the washing tub in such a manner as drifts in the washing tub. Therefore, a contact surface of the washing article with the cleaning liquid is increased, and furthermore, a penetrating force of the cleaning liquid into the washing article is enhanced. As a result, washing effects of the cleaning liquid on contamination of the washing article are enhanced.
As the washing method of Patent Publication 1 and the washing apparatus of Patent Publication 2, a pressure distribution is formed based on the rotation of the washing tub for the cleaning liquid that fills the casing, and thereby washing is performed. As a result, the present applicant can avoid the washing article from being damaged and enhance the washing effects of the cleaning liquid that fills the casing. In addition, the pressure distribution that is formed in the cleaning liquid influences behaviors of the washing article inside the cleaning liquid. Therefore, in order to achieve the washing effects sufficiently, it is necessary for the cleaning liquid filling the casing to form the pressure distribution effectively.
Then, the present applicant performed further verification for each construction of Patent Publication 1 and Patent Publication 2. As a result, as mentioned above, it was clarified that the pressure distribution is formed inside the cleaning liquid by rotation of concave and convex surface that is provided to the inside wall surface of the washing tub continuously in a circumferential direction. Namely, in the washing tub, the concave and convex surface is formed along the rotating direction thereof. Therefore, when the washing tub rotates, the cleaning liquid inside the concave portions moves toward the direction of the rotation by the convex portions, but the cleaning liquid itself tries to remain and stay. And thereby, swirling water currents in a spiral form are generated inside the concave portions.
By having the swirling water currents in a spiral shape formed in each of the concave portions, the cleaning liquid that fills the casing flows in a radial direction of the washing tub at a different flow rate in a form of an approximately concentric circle. Consequently, a pressure distribution is formed in the radial direction of the washing tub. The pressure distribution that is formed in the radial direction of the washing tub makes the washing article float inside the washing tub. As a result, the washing article that floats and drifts inside the cleaning liquid is spread. And thereby, the washing effect is advanced and at the same time, the washing article can be prevented from being damaged.